PSI - Issue 47

Andrea Iadarola et al. / Procedia Structural Integrity 47 (2023) 383–397 A. Iadarola / Structural Integrity Procedia 00 (2019) 000 – 000

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2.4. Tensile test and DIC system Tensile tests on the final resin mixtures have been carried out to verify the tensile properties provided by the material supplier and to assess the variability of the same properties with respect to the increase of total bio-content. Tensile tests have been performed using an MTS Landmark (25 kN load cell) provided by the laboratories of the Material Sustainability Engineering department of Centro Ricerche Fiat (C.R.F., Stellantis group). The tensile testing machine is equipped with a DIC system (LaVision GmbH, with LaVis 10 processing software) for the acquisition of the strain data. For this purpose, a random speckle (Fig. 2d) has been sprayed on the specimen surface, to track surface displacements and calculate the material deformation. The specimens object of this study have been tensile tested in quasi-static (0.1 mm/s) and dynamic (10 mm/s and 100 mm/s) conditions. Fig. 4 shows the tensile test setup: the testing machine together with the DIC system.

DIC camera

DIC light

Tensile testing machine

Fig. 4 . Tensile testing machine and DIC configuration.

The actual width and thickness of each specimen have been measured with a digital caliper (resolution of 0.01 mm) to compute the applied stress more accurately. Three specimens have been tested for each material at each strain rate condition. The values of modulus and strength have been computed considering the mean value of the three specimens. 2.5. Optical microscopy An optical analysis of the fracture surfaces on representative specimens has been carried out. For this purpose, a Dino-Lite AM3113T digital microscope has been used. Technical specifications are reported in Table 4.

Table 4. Technical specification of the digital microscope Specifications Light/ LED type

White

Magnification

10-70x, 200x